body{
            width:100vw;
            height:100vh;
            background: url('../../img/wechat/four.png') left top no-repeat;
            background-size:100% 100%;
        }
        .four_wrap{
            width:100vw;
            height:100vh;
            background:rgba(255,255,255,0.2);
            overflow: hidden;
        }
        .form_wrap{
            height: 200px;
            width: 100%;
            position: absolute;
            top: 0;
            right: 0;
            left: 0;
            bottom: 0;
            margin: auto;
            text-align: center;
        }
        .form_wrap .item{
            width: 80%;
            margin: 0 auto;
            height: 40px;
            line-height: 40px;
            font-size: 15px;
            margin-bottom: 10px;
            background: #e1e4ea;
            border-radius: 6px;
        }
        .form_wrap .item input{
            border: none;
            background: none;
            height: 40px;
            line-height: 40px;
            outline: none;
            font-size: 15px;
            width: 60%;
            margin: 0;
            padding: 0;
        }
        .submit button{
            border: none;
            height: 45px;
            width: 100px;
            margin-top: 20px;
            font-size: 17px;
            color: #fff;
            line-height: 45px;
            border-radius: 4px;
            background: #2c73a7;
        }
        .submit button:active{
            background: #ddd;
            color:#555;
        }